Mechanical performance of Q345 steel after corrosion: Experimental and theoretical investigation

Corrosion significantly influences the mechanical performance of steel, and the accurate prediction of stressstrain curves (S-SC) for steel after corrosion is crucial for the safety evaluation of in-service steel structures in engineering. This study focuses on assessing the degradation performance of Q345 steel following corrosion. Copper accelerated acetic acid salt spray testing (CASS) is employed to corrode Q345 specimens, and a power model is established to relate the mass loss rate to the corrosion time of Q345 steel. Uniaxial tension tests are then conducted to observe the mechanical behavior of corroded Q345 steel. Results indicate that the strength and ductility of Q345 steel decrease with an increase in the mass loss rate, and the yield plateau of the S-SC gradually shortens until it disappears. With the increase of corrosion time, the microstructure of the steel surface is transformed from spherical structure to needle-like structure. Two constitutive models are developed, incorporating the S-SC with and without the yield plateau, based on existing models. These models demonstrate good agreement with various test data, providing valuable insights into the mechanical behavior of corroded Q345 steel.